# CVE-2026-41991: Predictable Temporary File in GNU gzip > Local attackers can overwrite arbitrary files via symlink attacks in gzexe when mktemp is unavailable, requiring a patch to prevent data modification. - **Severity:** Low 2.0 (`CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 29 Jun 2026 - **Updated:** 29 Jun 2026 - **Also known as:** CLSA-2026-1783514299, CLSA-2026-1783934943, DEBIAN-CVE-2026-41991, ECHO-233f-78f2-a73b, GHSA-67v8-88jf-4x6q, JLSEC-2026-1264, RHSA-2026:33771, ROOT-OS-DEBIAN-11-CVE-2026-41991, ROOT-OS-DEBIAN-12-CVE-2026-41991, SUSE-SU-2026:22753-1, SUSE-SU-2026:22818-1, SUSE-SU-2026:22906-1, SUSE-SU-2026:22918-1, SUSE-SU-2026:3241-1, SUSE-SU-2026:3269-1, UBUNTU-CVE-2026-41991, openSUSE-SU-2026:11174-1, openSUSE-SU-2026:21371-1 ## What is CVE-2026-41991? CVE-2026-41991 is a low-severity path traversal vulnerability in GNU gzip, published on 29 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. ### Official description GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite. This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269 Weakness: CWE-377 (DEPRECATED: Insecure Temporary File) ## Which versions are affected by CVE-2026-41991? It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `gzip` | Red Hat:hummingbird:1 | All versions | 0:1.14-2.2.hum1 | | `gzip` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Micro 5.3 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Micro 5.4 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Micro 5.5 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server 12 SP5-LTSS | All versions | 1.10-4.17.1 | | `gzip` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server 16.0 | All versions | 1.13-160000.3.1 | | `gzip` | SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | All versions | 1.10-4.17.1 | | `gzip` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 1.10-150200.13.1 | | `gzip` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 1.13-160000.3.1 | | `gzip` | SUSE:Linux Micro 6.0 | All versions | 1.13-2.1 | | `gzip` | SUSE:Linux Micro 6.1 | All versions | 1.13-slfo.1.1_3.1 | | `gzip` | SUSE:Linux Micro 6.2 | All versions | 1.13-160000.3.1 | | `gzip` | openSUSE:Leap 16.0 | All versions | 1.13-160000.3.1 | | `gzip` | openSUSE:Tumbleweed | All versions | 1.14-2.1 | Products: Gnu Gzip. ## How do I fix CVE-2026-41991? Apply the vendor's patch. ## Is CVE-2026-41991 being exploited? There is no known exploitation of CVE-2026-41991 in the wild and no public exploit code. ## Other vulnerabilities in GNU gzip - [CVE-2004-0603](https://insights.sbomify.com/CVE-2004-0603/): Command injection in n/a (critical 10.0) - [CVE-2001-1228](https://insights.sbomify.com/CVE-2001-1228/): Memory corruption in n/a (high 7.5) - [CVE-2026-41992](https://insights.sbomify.com/CVE-2026-41992/): Global Buffer Overflow in GNU gzip (medium 6.9) - [CVE-2009-2624](https://insights.sbomify.com/CVE-2009-2624/): Memory corruption in n/a (medium 6.8) - [CVE-2010-0001](https://insights.sbomify.com/CVE-2010-0001/): Integer overflow in n/a (medium 6.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-41991 and fix it if it is affected. What it is: CVE-2026-41991 is a low-severity path traversal vulnerability in GNU gzip, published on 29 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-41991 in the wild and no public exploit code. Affected product: GNU gzip. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-41991/ (Markdown: https://insights.sbomify.com/CVE-2026-41991/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41991 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41991 - OSV: https://osv.dev/vulnerability/CVE-2026-41991 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-41991/ Summaries are generated and may contain mistakes; the official description above is the record.